Heated glazing

Abstract

A heated glazing suitable for an aircraft window including, two or more rigid sheets of glass and a network of fine metal resistance wires. Power lead-in strips providing power to the metal resistance wires are separated from one of the rigid glass sheets by a layer of polytetrafluoroethylene (Teflon) or a similar material which allows relative sliding between the power lead-in strips and the rigid glass sheet.

What is claimed is: 
     
       1. A heated glazing comprising: first and second rigid glass sheets;   a flexible interlayer sandwiched between said first and second rigid glass sheets;   a pair of power lead-in strips mounted at an interface between said first rigid glass sheet and said flexible interlayer; 17   a network of fine metal wires of electrical resistance extending between said pair of power lead-in strips; and   a sliding zone formed opposite said power lead-in strips, said sliding zone permitting relative sliding movement between said power lead-in strips and said second rigid glass sheet,   wherein the sliding zone projects into the interior of the glazing at least 5 mm beyond an inside edge of the power lead-in strips.   
     
     
       2. A heated glazing according to claim 1, wherein said flexible interlayer comprises first and second flexible interlayer portions, said first interlayer portion carrying said power lead-strips on a first face thereof and said second interlayer portion underlying the first interlayer portion and including a sliding material in a region opposite said power lead-in strips. 
     
     
       3. A heated glazing according to claim 1, wherein said flexible interlayer comprises first, second, and third interlayer portions, said first interlayer portion carrying said power lead-in strips on a first face thereof, said second interlayer portion including a sliding material in a region at least opposite said power lead-in strips, and said third interlayer underlying the second interlayer portion and being in contact with said second rigid glass sheet. 
     
     
       4. A heated glazing according to claim 2, wherein the sliding material is of a thickness equal to the thickness of the second interlayer portion. 
     
     
       5. A heated glazing according to claim 3, wherein the sliding material comprises at least two superposed strips whose combined thicknesses total to the thickness of the second interlayer portion. 
     
     
       6. A glazing according to claim 1, wherein the glazing has an outer lateral edge and the sliding zone has a lateral edge flush with the outer lateral edge of the glazing. 
     
     
       7. A glazing according to claim 6, wherein the glazing has a circumference and the sliding zone extends around the entire circumference of the glazing. 
     
     
       8. A glazing according to claim 1, wherein the interlayer includes a thermoplastic layer of polyvinyl butyral. 
     
     
       9. A glazing according to claim 1, wherein the interlayer includes a thermoplastic layer of polyurethane. 
     
     
       10. A glazing according to claim 1, wherein the interlayer includes a layer of polyvinyl butyral and a layer of polyurethane. 
     
     
       11. A glazing according to claim 1, wherein the sliding material is polytetrafluoroethylene. 
     
     
       12. A glazing according to claim 1, further comprising a third rigid glass sheet, said third rigid glass sheet being adjacent to said first rigid glass sheet. 
     
     
       13. A glazing according to claim 12, wherein said third rigid glass sheet has an edge offset from an edge of said first rigid glass sheet. 
     
     
       14. A glazing according to claim 1, wherein the power lead-in strips are adhered to the first rigid glass sheet. 
     
     
       15. A glazing according to claim 1, wherein the glazing is an aircraft glazing. 
     
     
       16. A heated glazing comprising: first and second rigid glass sheets;   a flexible interlayer sandwiched between said first and second rigid glass sheets;   a pair of power lead-in strips mounted at an interface between said first rigid glass sheet and said flexible interlayer;   a network of fine metal wires of electrical resistance extending between said pair of power lead-in strips; and   a sliding zone formed opposite said power lead-in strips, said sliding zone permitting relative sliding movement between said power lead-in strips and said second rigid glass sheets;   wherein:   said flexible interlayer comprises first and second flexible interlayer portions, said first interlayer portion carrying said power lead-in strips on a first face thereof and said second interlayer portion underlying the first interlayer portion and including a sliding material in a region opposite said power lead-in strips; and   the sliding material comprises at least two superposed strips whose combined thicknesses total to the thickness of the second interlayer portion.